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Experts explain: How the body works

Dr Claudia Pastides photo

Created: 6 August, 2018

Updated: 23 October, 2019

Our #It’sBodyAmazing campaign recently launched, celebrating the thousands of incredible functions your body carries out every day - often without you even realising.

And this week, we’ve asked our network of UK doctors to dive into the details behind some of the most brilliant things of bodies do, and how you can take a holistic approach to your own healthcare with our new Memberships subscription - designed to help you take complete control of every aspect of your health.

Keep up with some of the most amazing body facts we've been sharing on Instagram and Facebook.

Find out more about:

How the body heals itself

How we grow - from a small baby to a fully fledged adult

How the immune system fights against illness

How our memory works

How food is converted in fuel for various functions


How does our skin and bones heal themselves?

Answered by: Dr Claudia Pastides


Our bones and skin may seem less sophisticated than our other bodily parts and organs, but don’t let appearances deceive you as they are just as amazing. Our skin is the largest organ we possess and it is super skilled at healing itself. No matter whether it be a scratch, cut our serious wound, it will do its best to fix it.


First, our blood will form a clot (to stop blood loss and prevent anything from getting in
through the wound). Secondly, inflammation occurs (which brings with it lots of white cells
to fight infections, nutrients and enzymes to help the skin to heal). New skin and blood
vessels then form at the site and the injured area is gradually patched up.

Bones are equally good at healing themselves. Bone is a living material and, following a
break, the blood clot that forms around it later transforms into solid bone and bridges the
break. The amazing thing about children’s bones is that, because their bones are still
growing, the healing process happens much faster and their bones can even reshape.


How do we grow from being a small child into an adult?

Answered by: Dr Claudia Pastides


Bones grow by lengthening at either end through areas called ‘growth plates’. From as early as the days when a baby is inside the mother’s womb, new bone is formed at our growth plates and that bone gradually solidifies. This process keeps going until the growth plates fuse and the bones no longer grow (roughly age 14 for girls and 16 for boys).


How the rest of our body parts and organs grow isn’t quite as easy to explain! Everything
else does grow too, and in response to a variety of hormones and proteins, but different
tissues and areas of the body grow at different rates.

For example, our brains grow incredibly quickly after birth and until the age of 3 months - by which time they are already 50% of the size of an adult brain. But brain growth slows down from then on. Our eyeballs, though, are pretty much at their full adult size by age 3 and only continue to grow very little amounts until they finally stop at age 13. Fascinating stuff!


How does the immune system work?

Answered by: Dr Claire Ashley


One of the most important parts of the body is your immune system, which defends the body from bacteria, viruses, parasites, fungi and toxins which can infect you.  The immune system is made up of special cells, proteins, tissues, and organs, which include the spleen, bone marrow, and lymph nodes.

As I write this, my 2 year old son has come down with chicken pox.  Most of us will have experienced chicken pox in childhood, so I thought I would use chicken pox as a way to explain how our immune system works. Chickenpox occurs when your body is infected with a virus called varicella zosta.


If you imagine your immune system to be like an army, then the front line troops would be your white blood cells. These clever cells detect and destroy the enemy invaders, such as the varicella zosta virus. There are two types of white blood cells - the lymphocytes attack the enemy invaders, and the phagocytes engulf them. There are three types of lymphocytes - natural killer cells, T cells and B cells. B cells act to destroy germs by making proteins called antibodies.  

Your body remembers how to produce these antibodies so if you are re-infected by the same germ, your body will fight it off quickly and more easily.  This is why it is incredibly rare to get chickenpox twice, although not impossible. Chicken pox is normally infectious for about 5 days, until the last blister has crusted over.  At that point your immune system army has won the battle and you start to get better!

When you’re tired or stressed, your immune system can sometimes take the hit. Sometimes, it goes wrong on its own too - if you develop an autoimmune disease, it can start to attack healthy organs and tissues. It might also respond disproportionally to a risk too, causing allergies to develop to certain stimuli (like pollen).

Struggling to stay fighting fit? Find out more about how our Memberships plan could work for you - with exclusive access to expert, tailored health advice.


How does the memory work?

Answered by: Dr Helen Garr


In simple terms, forming memories comes down to electrical pathways and chemicals! Nerve cells called neurons connect with each other in the brain using electricity and chemicals called neurotransmitters. Your brain has about one billion neurons which all connect with each other many times, resulting in over one trillion connections.

Memories are formed when these connections between nerve cells are strengthened in a process called Long Term Potentiation. Your memories can be either short-term or long-term.


Your short-term memory can hold between and 4 and 9 items for around 30
Seconds. Some memories make it through to long-term storage though. New memories are created in the area of the brain called the hippocampus and over time they are moved to the
outer part of the brain called the cortex where they become long term memories.

Find out more about how memories are stored, and how you can improve yours, on Dr Helen Garr’s blog post.


How our bodies turn food into energy

Answered by: Will Hawkins


Every single part (cell) of the body needs energy to work. This energy comes from the food we eat. Our bodies digest the food we eat by mixing it with fluids (acids and enzymes) in the stomach and saliva glands in the mouth.

When we digest food, the carbohydrate (sugars and starches) in the food breaks down into another type of sugar, called glucose. Proteins are broken down into strings of amino acids called peptides (used for every single metabolic function in the body), and fats are broken down into fatty acids and glycerol (again, used for energy as well as multiple other bodily functions).

The stomach and small intestines absorb the glucose and then release it into the bloodstream. Once in the bloodstream, glucose can be used immediately for energy or stored in our bodies, to be used later.


Insulin - a hormone made in the pancreas - helps our cells convert glucose into energy, and it helps our bodies store extra glucose for use later. For example, if you eat a large meal and your body doesn't need that much glucose right away, insulin will help your body store it to convert to energy later.

Insulin does this by turning the extra food into larger packages of glucose called glycogen. Glycogen is stored in the liver and muscles.

Insulin also plays a vital role in how our bodies use/store fat and protein. Almost all body cells need protein to work and grow. The body needs fat to protect nerves and make several important hormones. Fat and protein can also be used by the body as an energy source, but this is dictated by your insulin production and blood sugar levels, of which can be influenced by several factors such as, activity levels, fitness levels, diet, and hormonal status.

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Topics: Health and Wellbeing, Fitness